A typical arbor for a hole saw or other hole cutter includes an arbor body defining a threaded end portion that is threadedly engageable within the end plate of a hole saw to fixedly secure the hole saw to the arbor. A pilot drill is receivable within the threaded end portion of the arbor body and extends through the center of the hole saw. The arbor body defines a shoulder that is axially spaced adjacent to the threaded end portion and is engageable with the end plate of the hole saw. The arbor further includes a pin ring that is axially spaced from the threaded end portion and fixedly secured to the arbor body by a set screw. A drive plate is slidably mounted on the arbor body on the opposite side of the pin ring relative to the threaded end portion, and includes a pair of diametrically opposed drive pins that extend into corresponding through holes formed in the pin ring. The ends of the drive pins are received in corresponding drive holes formed in the end plate of the hole saw to rotatably drive the hole saw. A lock nut is threadedly mounted on the arbor body on the opposite side of the drive plate relative to the pin ring.
In order to mount the hole saw to the arbor, the end plate of the hole saw is threaded onto the threaded end portion of the arbor body until the end plate contacts the shoulder of the arbor body. The end plate is then unthreaded or backed away from the shoulder just enough to align the drive holes in the hole saw with the drive pins of the arbor. Then, the lock nut is threadedly engaged with the drive plate to, in turn, lock the drive plate to the pin ring and secure the arbor to the hole saw.
One of the drawbacks associated with this type of arbor is that when the hole saw is backed away from the shoulder to align the drive pins with the drive holes of the saw, a gap is formed between the end plate of the saw and the pin ring of the arbor. This gap can lead to off-axis wobble of the hole saw, particularly with larger diameter hole saws and/or hole saws that operate at relatively high rotational speeds. Off-axis wobble can cause undesirable vibration of the hole saw during cutting that can reduce the cutting life of the hole saw and/or create a degree of inaccuracy in the cut that is greater than otherwise desired.
Accordingly, it is an object of the present invention to overcome one or more of the above-described drawbacks and/or disadvantages of the prior art.